package com.jeeplus.modules.tools.utils;

import org.apache.commons.lang3.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Service;
import org.springframework.context.annotation.Lazy;

/**
 * @author Administrator
 * @title: SpringUtil
 * @projectName JeePlus
 * @description: TODO
 * @date 2019/9/913:49
 */
@Service
@Lazy(false)
public class SpringUtil implements ApplicationContextAware, DisposableBean {
    private static ApplicationContext applicationContext = null;
    private static Logger logger = LoggerFactory.getLogger(SpringUtil.class);

    /**
     * 去的存储在静态变量中的ApplicationContext
     *
     * @return
     */
    public static ApplicationContext getApplicationContext() {
        assertContextInjected();
        return applicationContext;
    }

    /**
     * 从静态变量applicationContext中去的Bean，自动转型为所复制对象的类型
     *
     * @param name
     * @param <T>
     * @return
     */
    public static <T> T getBean(String name) {
        assertContextInjected();
        return (T) applicationContext.getBean(name);
    }

    /**
     * 从静态变量applicationContext中去的Bean，自动转型为所复制对象的类型
     *
     * @param requiredType
     * @param <T>
     * @return
     */
    public static <T> T getBean(Class<T> requiredType) {
        assertContextInjected();
        return (T) applicationContext.getBean(requiredType);
    }

    /**
     * 清楚SpringContextHolder中的ApplicationContext为Null
     */
    public static void clearHolder() {
        if (logger.isDebugEnabled()) {
            logger.debug("清除SpringContextHolder中的ApplicationContext:" + applicationContext);
        }
        applicationContext = null;
    }


    /**
     * 检查ApplicationContext不为空
     */
    private static void assertContextInjected() {
        Validate.validState(applicationContext != null, "applicaitonContext属性未注入, 请在applicationContext.xml中定义SpringContextHolder.");
    }

    /**
     * 实现ApplicationContextAware接口，注入Context到静态变量
     *
     * @param applicationContext
     * @throws BeansException
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        SpringUtil.applicationContext = applicationContext;
    }

    /**
     * 实现DisposableBean接口，在Context关闭时清理静态变量
     *
     * @throws Exception
     */
    @Override
    public void destroy() throws Exception {
        SpringUtil.clearHolder();
    }

}
